If a tweeter has a 100 watt specification, at what frequency can it handle this amount of power? The resonance frequency is 850Hz and the recommended crossover frequency is at 3000Hz. Can a tweeter handle more power at a higher frequency and does the crossover order have any effect power handling? Thanks, Adrian.

A 10W sine wave will probably overheat the voice coil of the tweeter. The crossover has nothing to do with power handling. A sine wave played at 10kHz with 10W power is going to be the same with or without the crossover.

Power handling of tweeters is quite confusing........you are not alone!
I respectfully disagree with the second post; crossover frequency DOES alter power handling at least if we are listening to music. (true, cotdt WAS discussing sine waves)
Usually a manufacturer will "de-rate" the power handling of tweeters and mid-range units if used at a lower frequency. Copious sheets of data from Vifa, DIY application books from Philips etc confirm this.
Secondly, the specification sheets can be confusing because they will often give an RMS figure and a "music power" figure. The latter is always higher. The 'music' figure recognises the real world situation where we usually listen to music which is almost always highly variable in its content........now bass notes.....then a lot of treble etc. The nature of music means that a driver seldom has to carry the same frequency at a constant level for very long. Hence the "music" rating is sometimes called "the instantaneous" power rating. This leads some manufacturers to give a steady state or RMS figure of, say 30 Watts, and then an instantaneous figure of far higher......200 or so.
Dynaudio was often quoting figures in the 1000 watt area.
This is confusing.....
Now if you are asking this question with a view to using a tweeter in a system you will find that a 100 watt rating will probably be fine in a domestic situation. You will in fact probably only be using a few watts anyway and the odd loud transient will not be more than a few 10's of watts and last for a few milli-seconds. Some serious namufacturer will quote TIME (i.e duration of the signal) and power which is much more helpful.
There is a paradox here to. If an amp "clips" there can be a spray of high frequency distortion products that the tweeter may not handle well. So the advice is often given that it is better to use a higher power amp that is not driven into clipping than a small 10 watt version that may be driven into overload and damage speakers. Okay? So 100 may be "safer" than a smaller 10 watt one.

Now cross over order. Here there are two items running. Higher order networks reduce the stress on a driver by (A) limiting the mechanical excursion of cone/dome because the diaphragm movement increases with decreasing frequency and (B) they will reduce thermal stress. The power in most music is in the lower frequencies and reducing them reduces the power fed to the driver.

Hope this is helpful. I started looking at this material about 40 years ago and it is not easy to get your head around at first.
I would encourage you to read around the area and persevere as it makes sense eventually.
I haven't tried it but "speaker power handling" in Google will probably reveal a mountain of stuff.....
Good luck,
Cheers, Jonathan (Brisbane)

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It's a Vifa D25 AG, thankyou Jonathan for your detailed response, the power figure is 100 watts rms but my receiver is rated at 120 watts rms, would this tweeter be ok with a crossover at 3000Hz? Adrian. Brisbane.

That tweeter is okay with that amp, so long as it's not driven to clipping, using at least a 12db/oct crossover at 3k.

That style of tweeter is really something less than able to handle a continuous 30 watt sine input, over double the resonant frequency, without overheating. Below resonance you can mechanically destroy the leadwires or suspension with a couple watts and not a very long time. At 2k and 6db/oct, for example, I'd recommend a 35 watt amp or less, run clean.

Hi Keswick
Also most power handling ratings are "System Power" ratings so if most of the music power is in the bass and mid-range then the tweeter is really only handling about 10% of the music signal.
If the amp is putting out 100 watts music then the tweeter really is getting only about 10 watts, that tweeter does need a second order XO tho and i crossed mine a lot higher 4500 LR in a 3-way

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I agree with post #2. The tweeter has a couple of factors that result in very low actual power being delivered to its voice coil.
1. By using a crossover at or above 2k Hz, much of the "power" in the music signal is filtered out because it is occurring at frequencies that are lower than this.
2. The relative power that does occur in music signals above 2k Hz (for instance) is less than for below this frequency. This has to do with the power spectrum of music, which is concentrated in a band between 100Hz and 2000Hz or there abouts.

This is why a manufacturer can state "100W power handling". What is not often stated is "only when an appropriate crossover is used" although sometimes you do see the crossover spec. mentioned. There is ABSOLUTELY NO WAY that a tweeter will last very long if 100W of power are fed to it! Have you ever seen a tweeter voice coil? The wire is like thread. There is very little nearby mass into which heat can dissipate, especially so for neo tweeters. Remember 99% of power input is dissipated as HEAT! No way in H-E double hockey sticks can a tweeter actually accept much power input my friend.

On the flip side, I often see Tang Band tweeters quoted as having 10W power handling. This may be the actual spec for broad band power input, at least one that I could believe for an instant.